As is generally well known, during installation of drywall sheets in a corner region of a room, the new drywall sheet to be installed often leaves undesirable gap with already installed drywall sheet on the adjacent wall. Accordingly, this new drywall sheet must be cut, generally at an angle, in order to provide proper fit. When using conventional rigid T-square, the installer must try to tip the square, hold it in place, and finally make the cut, which can be slow and cumbersome.
Prior to the conception and development of the present invention, efforts have been made to alleviate difficulties arising during installation of the drywall sheets.
U.S. Pat. No. 7,082,692 issued to Shapiro discloses an adjustable ruler that includes two elongated ruler members and an adjustable clamping members enabling these rulers to be frictionally secured at various angles to one another.
U.S. Pat. No. 6,260,283 issued to Abernathy et al. discloses another form of the multi-functional carpentry tool that includes a base plate having opposed front and back major surfaces, and at least one side edge bearing surface perpendicular to the front and back surfaces. A pivot ruler is secured to the base plate and extends across and parallel to the front major surface and outwardly from the base plate. The pivot ruler includes an elongated marking member having opposing straight side edges. A longitudinal slot is formed in the marking member parallel to and between the opposed side edges of the marking member. A pivot attachment device is received through the slot of the marking member and into the base plate for pivotably attaching the marking member to the base plate. The marking member is slidable across the front major surface of the base plate a distance equal to the length of the slot.
U.S. Pat. No. 6,049,990 issued to Holland discloses yet another multifunctional layout tool that is capable of performing the functions of an adjustable square, adjustable T-square, try square, combination square, protractor, angle duplicator, depth gauge, rip gauge, rafter-stair layout tool, and compass. The tool comprises a generally T-shaped squaring base, mounting an elongated sliding rule. The base is comprised of a body defining a central flared channel to receive the rule and a pair of squaring arms extending from the body, defining a squaring edge along an end of the base, perpendicular to the channel. The rule is disposed in and extends out of the channel, between the squaring arms. The rule is a blade having a rounded end, a square end, and a central longitudinal slot. A fastener anchored to the base, extending through the rule slot, maintains the rule within the channel. Protractor indicia disposed within the channel and corresponding vernier indicia on the rounded end of the rule measure disposition angles of the rule when the rule is fully extended. Direct reading intermediate angle indicia, comprising paired parallel lines can be disposed within the flared portion of the channel. Direct measurement indicia along the blade initiates from the square end of the blade; and radius measurement indicia for drawing a circle of a given radius, measured from the squaring edge of the base, initiates from the distal end of the blade slot. Alternatively, a vial level may be disposed generally parallel with the squaring edge, in a recess defined in the back of the base.
U.S. Pat. No. 7,269,909 issued to Barbieri discloses a rafter layout tool that includes a protractor member, measurement indicator arm and 90 degree arm that move up and down and side to side for different size lumber which is pivotally connected to the base of the protractor member and incorporating means for indicating pitch markings on said protractor. Extending linearly along the measurement indicator arm is a bounded slot providing means for slideably up and down and attaching the 90 degree arm ably to slide side to side and up and down for different size lumber.
U.S. Pat. No. 6,134,795 issued to Hitchcock and U.S. Pub. No. 2006/0168835 published to Casner et al. provide other devices suitable for installing drywall.
While the above prior art devices are capable of facilitating drywall installation, there is a continuing need for a multi-functional combination carpentry tool providing functional and structural improvements.